1. Field of the Invention
The present invention relates to a method for forming a blanked piece high in its degree of freedom of design and excellent in its accuracy of a configuration and a manufacturing method of a laminated body and a laminated iron core using the blanked piece formed by the above-described method.
2. Description of the Related Art
A motor is usually used as a driving source of a refrigerator, an air conditioner, a hard disk drive, a power tool or the like. In recent years, the motor is also used as a driving source of a hybrid car. A laminated iron core which forms a rotor and a stator respectively as main components of the motor is formed in such a way that a prescribed number of iron core pieces manufactured by blanking or stamping out a thin electromagnetic steel plate to a prescribed configuration are laminated and the laminated iron core pieces are fastened and connected together. Then, a winding is applied to the laminated iron core for the stator, a shaft is attached to the laminated iron core for the rotor and both the laminated iron cores are accommodated in a casing, so that the motor is completed. Here, as a unit for fastening and connecting together the iron core pieces adjacent in a vertical direction in the laminated iron core pieces, a caulking or welding method is used from the viewpoint of a cost performance and a working efficiency.
On the other hand, when a high torque and a low iron loss are preferentially considered in a motor property, a method for fastening and connecting together the iron core pieces by using a resin material is used in place of the caulking or welding method. For instance, Japanese Patent No. 5357187 as Patent Literature 1 discloses that in a production of a split type stator 100 shown in FIG. 7, a unit laminated iron core 101 which forms the split type stator 100 is manufactured by laminating, and fastening and connecting together iron core pieces 102 shown in FIG. 8. Here, the iron core piece 102 includes a product piece part 103 forming the unit laminated iron core 101 and a production jig piece part 104 fitted and fixed to the product piece part 103 by a push back. A winding 101a is shown in FIG. 7. Further, the push back refers to a working method that a blanking or stamping work in a half blanked state is carried out in which a movement of a blanking or stamping punch is stopped halfway, or a blanking or stamping work in a completely blanked state is carried out in which the blanking or stamping punch is moved by the thickness of an electromagnetic steel plate to substantially separate a blanked or stamped part from the electromagnetic steel plate, and then, the blanked or stamped part is pushed back to a blanked or stamped hole formed in the electromagnetic steel plate.
The product piece part 103 of the iron core piece 102 includes a sector shaped back yoke piece part 105 and a teeth piece part 106 protruding inside in a radial direction from a central part of an inner side of the back yoke piece part 105. In a central part of an outer side of the back yoke piece part 105 (a central part opposite to the teeth piece part 106), a fitting recessed part 107 is provided to which the production jig piece part 104 is fitted and fixed. In both ends of the back yoke piece part 105, an engagement recessed part 108 and an engagement protrusion 109 are respectively provided with which the adjacent product piece parts 103 are engaged.
Further, the production jig piece part 104 of the iron core piece 102 includes a fitting protrusion 110 fitted and fixed to the fitting recessed part 107 of the back yoke piece part 105 and a gripping protrusion 111 provided to protrude on the fitting protrusion 110. In order to reduce a contact area of the fitting recessed part 107 of the back yoke piece part 105 and the fitting part, in an end part of the fitting protrusion 110, a disengaging recessed part 112 is provided. At both sides of the fitting protrusion 110, disengaging recessed parts 113 and 114 are provided. Inside the fitting recessed part 107 of the back yoke piece part 105, disengaging recessed parts 115, 116 and 117 are respectively provided so as to be opposed to the disengaging recessed parts 112, 113 and 114 of the fitting protrusion 110 fitted and fixed thereto. Further, in a central part of the gripping protrusion 111 of the production jig piece part 104, a caulking and connection part 120 is formed with a front surface side as a fixing recessed part 118 and a back surface side as a fixing protrusion 119 which binds and connects together the production jig piece parts 104 adjacent in a vertical direction when the iron core pieces 102 are laminated in the vertical direction.
In such a structure, when the laminated iron core pieces 102 are caulked and connected together, as shown in FIG. 9, the caulked and connected production jig piece parts 104 form a fixing jig 121 which temporarily joins and connects together the laminated product piece parts 103 in a laminated state. When the product piece parts 103 which are temporarily joined and connected by the fixing jig 121 are integrally molded with an insulating resin 122 by a die cast molding, the temporarily joined product piece parts 103 can be actually joined and connected. Then, after the winding 101a is applied to a part where the teeth piece parts 106 are actually joined and connected together, the fixing jig 121 is slid in a direction of lamination of the iron core pieces 102, for instance, a direction A. Thus, the unit laminated iron core 101 which has no caulking part can be separated from the fixing jig 121 which has the caulking and connection part. An operation that the production jig piece parts 104 mutually adjacent in the vertical direction are bound and connected together through the caulking and connection parts 120 is referred to as a dummy caulking and the fixing jig 121 formed by the dummy caulking is referred to as a dummy caulking block.
Patent Literature 1: Japanese Patent No. 5357187